Wave reproducing device and process concerning the same



Sept. 15, 1931. c. P. MADSEN 2 WAVE REPRODUCING DEVICE AND PROCESSCONERNING THE SAME Filed Aug. 5, 1924 2 Sheets-Sheet l A TTORNE V mmy/AINVEN TOR c. P. MADSEN 1,823,457

Sept. 15, 1931.

WAVE REPRODUCING DEVICE AND PROCESS CONCERNING THE SAME Filed Aug. 5,1924 2 Sheets-Sheet 2 Patented Sept. 15, 1931 UNITED STATES PATENT@FFICE CHARLES P. MADSEN, OF NEW YORK, N. Y., ASSIGNOR, BY MESNEASSIGNMENTS, TO WILLIAM W. VARNEY, OF BALTIMORE, MARYLAND WAVEREPRODUCING DEVICE AND PROCESS CONCERNING THE SAME Application filedAugust 5, 1924. Serial No. 730,152.

The object of my invention is to simplify the construction of mechanicaldevices for transforming the mechanical vibrations given the needle byphonograph record or other mechanically operating device into airvibrations, thus generating audible sound and to improve the perfectionof this transformation.

While the invention is intended primarily for phonographs and moreparticularly in connection with lateral cut records, it may also be usedwith hill and dale type of record, and is also useful in connection withgenerating sound from other sources than that of the phonograph record,as, for instance, it may be used in connection with electro-magneticallyoperated devices, such as the loud speaking telephone and used inconnection with public address systems, or in connection with radiodevices.

In the usual re-production of sound a diaphragm or other vibrating bodysecured at or near its periphery and vibrated at or near its center, isused, which device is the best that was known and gives results notaltogether satisfactory, producing in many cases distortion and impuretones. The above difficulties I have in a great measure overcome.

A further object of my invention is the direct production of wavevibrations and their dispersion in space, thus avoiding amplification.

A further object of my invention is an im proved means of mounting thewave producing appliance.

A further object of my invention is an im proved means of detachablyconnecting the mechanically operated sound producing appliance tofacilitate transportation requirements.

A further object of my invention is an improved vibration producer.

VVith the foregoing and other objects in view, my invention consists ofthe methods employed, combination and arrangement of systems, apparatusand means as hereinafter specifically provided and illustrated in theaccompanying drawings wherein is shown the preferred embodiment of myinvention, but it is understood that changes, variations andmodifications may be resorted to which come within the scope of theclaims hereunto appended.

For practical reasons, devices for transforming the groovedconfigurations of a phonograph record. or other mechanical de vice, intoair vibrations or other vibrations are made of metal, and seriousdefects are caused thereby. When a metal, or other resonant rocker-arm,is mounted as is usual upon a metal or other resonant support for thediaphragm and air chamber or other vibrating means, molecular vibrationsare transmitted from the rocker-arm supporting the needle, or othermechanical device, into the frame or support. Since the soundconductivity of this system is greater because of its greater mass thanthat of the system comprising the rocker arm and mica disc, the airvibrations imparted to the air column from the two diflerent sourceswill be out of phase or step, thus resulting in discord and distortion.

Giving a concrete example of the above, I have discovered that bycompletely insulating the rocker-arm from the sound box metal containerby a system of rubber gaskets that the above defect is almost completelyovercome and other new and most unexpected results are produced. If thewashers be placed under a high compression instead of resisting thevibrations of the rocker-arm, as would be expected, it instead transmitsthe motion more effectively, but it cannot, on the other hand, turn morethan a very small are. It can thus be subjected to enormous shockwithout injury to the vibrating appliance or other parts to which it isconnected, and thus becomes fool-proof. But, furthermore, the resistanceto motion of the order of that produced by the record groove is so veryslight that it diminishes record wear and surface noises materially.

As intimated above, this device makes it practical to transmit thevibrations direct to the air without the intermediary of a diaphragm ofthe usual type. This is made possible by the fact that although therubber washer when under compression will permit motion to the degreeimparted by the record i with the groove.

with almost no resistance, its resistance to motion beyond this degreeis extremely high and it permits of the support thereon or connectiontherewith of relatively heavy or clumsy members, which cannot be donewhen a rocker arm is used tensioned or supported by springs or otherwiseas is now common in the art.

In the drawings of the herein-described embodiment of one application ofmy invention, Fig. 1 is a perspective view of a small, portablephonograph, or talking-machine; Fig. 2 is an enlarged view of a sectionof a portion of the same taken through line 22 of Fig. 1; Fig. 3 is anenlarged sectional view taken through the center of the securing cone:

Fig. 4 is a development of the resilient cone shown mounted in the abovefigures. Fig. 5 is an enlarged view taken through line 5 of Figs. 1 and2; Fig. 6 is a view similar to that shown in Fig. 5 before the severalparts are Compressed into position. Fig. 7 shows a modification of themeans of maintaining in position the support 5 when vibrated in arectilinear movement for hill and dale repro duction; Fig. 8 shows aview in elevation of the tone arm carrying support 5, and Fig. 9 shows amodified means of securing the resilient vibrating means together andFig. 10 shows an enlarged sectional view of the clamping cups and aportion of the cone in relative position before clamping.

Similar numerals refer to similar parts throughout the several views.

1 is a phonograph box containing the driving mechanism and means ofrevolving disc 2.

3 is a surface to be vibrated, oscillated, or otherwise moved to causeor engender waves and may be made of any suitable flexible material.which will give a maximum of surface for a minimum of weight as, forinstance. aluminum, hard rubber, celluloid, bakelized or plain paper. Ihave found paper, formed as shown in 4 and provided with a gummed edge 4or secured as shown in Fig. 9 when made of stiff material, to be mostdesirable, convenient and economical. In this specification when I usethe term surface. I mean that which is vibrated in contact with a mediumto form desired waves, and include in such term such necessary thicknessor body as to maintain the same in shape.

The support, or rocker-arm, 5 carries the member upon which is surface3, and said support 5 may be made of any suitable material. I use analloy of aluminum and magnesium known commercially as duraluminum. It ispreferably fulcrumed and gives an oscillating movement to surface 3.This in the case of lateral cut records is accomplished by placing thebell crank at right angles to the groove of the record as shown in Figs.1, 2, 5 and 6, while in the case of hill and dale records, it can beplaced parallel This fulcrum is, however,

not absolutely essential, and pleasing results, although not soeflicient, can be obtained by translating the motion into directrectilinear motion by means of the modification shown in Figure 7.

6 is the re-producer carrier, fulcrumed at 7 to post 19 which isrevolvably mounted in the cover of phonograph box 1, as is sometimesdone in small portable phonographs.

8 is the fulcrum pin which carries rockerarm 5 by means of rubberbushing 9. rubber washers 10 and 11, metal washer 12, and nut 13. 8 asshown is a stud screwed into arm 6. Upon setting up nut 13, bushing 9and rubher washers 10 and 11 are highly compressed and cause the variousparts to appear substantially rigid, which is not the fact, asheretofore explained.

To obtain the best results, the bushing 9 is made considerably longerthan the thickness of the rocker-arm 5, as illustrated in Fig. 6, and,furthermore, fits both the hole in the rocker-arm and the fulcrum 8 verytightly. hen the washers and bushings are compressed by the nut 13 thetension of the bushing and washers will be sufficient to properlysupport the bell-crank 5. I find it also preferable to use for thisbushing a rubber having considerable filler, as, for instance, a

grade of stock used for the outer tires, or

shoes, of automobiles, while for the side washers 10 and 11, I prefer touse a substantially pure vulcanized gum like that from which ordinaryrubber bands are made. Other materials will answer for the purpose, andI do not wish to limit my invention to the specific use of rubber; forinstance, guttapercha, balata, vulcanized chicle, or any of thevulcanized vegetable oils, as, for instance, corn oil, will answer,although not quite so permanent under high compression as purevulcanized caoutchouc.

14 is the tracing member, needle, or pin, ordinarily used in phonographreproduction.

I have found that a ery efficient and pleasing result is obtained bymounting directly upon support 5 a cone-shaped object of paper or otherlight material. To do this I preferably fasten on top of the rocker-arm5 a very light, small metallic cone 16 having a vertical threaded stem15 on the inside. I provide another removable small metallic cone 17,with a threaded nut 18, to fit stem 15 and the relatively large, thinresilient material cone is clamped between the two. Cone-shaped objectsmay be supplied to the user flat with a triangular section cut out and ahole in the center, as per sketch shown in Fig. 4, when plain paper isused as the material of the cone, or as shown in Fig. 9 I

when stiffer material is used. One side of the flattened cone from whichthe triangular section is cut is provided with a material 4 which willbecome adhesive by moistening. These cones may be of various sizes, butpreferably are in the flat the same size as the record, which is fromten to twelve inches in diameter. A quantity of them can, therefore, becarried in the record container. The balance of the re-producing systemis very small and light and can be carried in the confines of a verysmall portable machine.

To set up the device for operation it is only necessary to moisten thegummed edge of the flattened cone and set it up and insert it betweenthe cups 16 and 17, securing it in position with screw nut 18 when thedevice is ready for use. In transporting the device this paper cone isremoved and can be flattened again by moistening the joints, but sincethey are so cheap it is preferable to dis card it and use another onefor the neXt set up.

I may also instead of the paper cone provided with a gummed edge, asdescribed above, use a cone of other resilient material with a permanentfastening means which can be readily demounted and set up again. I havefound, for instance, that very thin hard vulcanized rubber can be usedin this way. In this case I provide one edge with an extra flap betweenwhich and the body of the cone the other edge is inserted. If, now, thecone is of slightly greater angle than that of the holding cups, theedges will, in compressing the cups, be forced together and in removingthe cups will readily come apart again as shown in Fig. 10.

Having thus described my invention, what I claim and desire to secure byLetters Patent is 1. A phonograph sound reproducing device comprising arocker arm supported by an organic, resilient material, a small metalliccup rigidly mounted thereon, a removable cup fitted within said firstnamed cup, means for clamping said two cups together, and a relativelylarge cone diaphragm clamped between said two cups.

2. A phonograph reproducer comprising a supporting means provided withan elastic element within which is positioned a member provided with aneedle-holding device, and a diaphragm mounted on the said member, saidelastic element being in a compressed condition, and means forcompressing said elastic element.

3. A reproducer for a phonograph provided with a carrier mounted toswing over a record to be played, a bell-crank carried by said carrierfulcrumed thereto said bellcrank having secured at one end thereof astylus and at the other end thereof a vibrating member rigidly securedthereto and wholly supported thereby, said vibrator being substantiallyof a conoidal shape a side of which is substantially parallel to thedisc to be played.

4. In an organized phonograph a reproducer member in part consisting ofa vibrating conically shaped member, a reproducer carrying arm pivotedto swing over a record to be played and carrying said conically shapedvibrating member and means for mounting said conically shaped vibratingmember with reference to said carrying arm so that said carrying arm anda side of said vibrating member are substantially parallel, a stylusoperating said conically vibrating member rigidly attached thereto bymeans of a carrying member provided to receive a stylus and the axes ofsaid stylus and the said conical vibrating member being substantiallyparallel.

5. A phonograph reproducer consisting of a supporting member, avibrating member, a vibrating adjusting means, a fulcrum between thesupporting member and the vibrating member said fulcrum having anelastic element positioned between the said two members and means forchanging the density of said elastic element.

6. A phonograph vibratory member adjuster consisting of a styluscarrying member and fixedly secured thereunto, an air vibrating memberforming substantially a single unit floated in an elastic element, anelastic element floating said stylus carrying member, and means forvarying the density of said elastic element.

CHARLES P. MADSEN.

